The present invention relates to improvements in the data acquisition process for biometric sensors such as the acquisition of fingerprints by fingerprint recognition sensors.
Automated biometric sensors are used to establish or authenticate the identity of a person based on biological characteristics that are in possession of the person. One such biometric sensor is a fingerprint recognition sensor. Various types of fingerprint recognition sensors are known including optical sensors, capacitance sensors, thermal sensors, and ultrasonic sensors.
The present invention uses quantitative measurements of forces that an individual applies to a fingerprint sensor to improve the acquisition process. The system and method of the present invention illustratively creates a lookup table of force measurements for multiple fingerprint sensing technologies in order to acquire the highest quality fingerprint images. The optimal finger force to produce the best results varies by fingerprint sensing technology.
The present invention provides an improved fingerprint acquisition algorithm through a constant monitoring of forces applied to a fingerprint sensor by the user's finger. This monitoring allows for acquisition of the fingerprint image to occur when the force level is in an optimal range. The optimal range is illustratively listed in a lookup table accessible by the device. The acquisition algorithm also provides feedback/guidance to the user on how much pressure to apply on the device by comparing the actual force applied to the optimal pressure value for the particular device retrieved from the lookup table.
The system and method of the present invention may be integrated in any fingerprint recognition system. Primary applications include, but are not limited to: law enforcement, registered traveler programs, financial services, healthcare, telecommunications, social services, electronic commerce, and access control.
The present invention improves the quality of fingerprint images that are acquired by the fingerprint recognition system by providing a lookup table of force measurements for different fingerprint sensor technologies, and by providing constructive feedback to the user. These improvements permit higher quality images to be acquired by the fingerprint system, leading to improved matching performance. Image quality is a predictor of matching performance for detection and recognition systems. Knowledge of the force level significantly increases the average reported image quality score by about 20% if knowledge of the fingerprint sensing technology and applied force is known. Correspondingly, fingerprint matching performance can improve over 10% for optical and capacitance technologies if knowledge of the fingerprint sensing technology and applied force is known.
The present system and method analyzes the impact of human interaction with fingerprint sensors and the implications on image quality and subsequent algorithm performance. The significance of user interaction with various fingerprint recognition sensor technologies is apparent, given that fingerprint recognition is the most widely used of the biometric technologies, with popular applications in law enforcement (e.g., the Integrated Automated Fingerprint Identification System—IAFIS), access control, time and attendance recordkeeping, and personal computer/network access. Fingerprint identification is also used with personal data assistants, mobile phones, laptop computers, desktop keyboards, mice, and universal serial bus (USB) flash media drives.
In an illustrated embodiment of the present disclosure, a method of optimizing performance of a fingerprint sensor comprises detecting placement of at least one finger on the fingerprint sensor, determining a force applied to the sensor by the at least one finger, determining whether the force is within an optimal force range for the fingerprint sensor, providing feedback to a user to adjust the applied force if the applied force is outside the optimal force range, and capturing at least one fingerprint image with the fingerprint sensor after the applied force is in the optimal force range.
In another illustrated embodiment of the present disclosure, a method of optimizing performance of a fingerprint sensor comprises storing a plurality of optimal force ranges and optimal image quality scores and for each of a plurality of different fingerprint sensors in a database accessible by a computer, and receiving captured data from a remote fingerprint sensor at the computer. The captured data includes a remote fingerprint sensor identification, an image quality score for at least one captured fingerprint, and a force parameter for the at least one captured fingerprint. The method also includes identifying a particular type of fingerprint sensor being used as the remote fingerprint sensor based on the fingerprint sensor identification, comparing the received image quality scores and force parameters for the at least one fingerprint to the optimal force ranges and image quality scores for the particular type of fingerprint sensor stored in a database, and taking an action if at least one of the received image quality scores and the received force parameters differ from the optimal force ranges and optimal image quality scores by a predetermined amount.
In yet another illustrated embodiment of the present disclosure, a sensing apparatus includes a fingerprint sensor having a sensing portion to receive at least one finger of a person, a force sensor coupled to the fingerprint sensor to detect a finger pressure on the sensing portion of the fingerprint sensor, a processor coupled to the fingerprint sensor and the force sensor, an indicator coupled to the processor, and a memory coupled to the processor. The memory stores an optimal force range for the finger pressure applied to the sensing portion. The apparatus also includes software executable by the processor for detecting placement of at least one finger on the fingerprint sensor, for determining a force applied to the sensor by the at least one finger, for determining whether the force is within an optimal force range for the fingerprint sensor, for providing feedback to the indicator to advise a user to adjust the applied force if the applied force is outside the optimal force range, and for capturing at least one fingerprint image with the fingerprint sensor after the applied force is in the optimal force range.
In still another illustrated embodiment of the present disclosure, a method of optimizing performance of a fingerprint sensor includes determining an optimal force range for initiating fingerprint acquisition in each of a plurality of different types of fingerprint sensors, storing the optimal force ranges for initiating fingerprint acquisition in a plurality of different types of fingerprint sensors in a database in a memory accessible by a computer, an optimal force range being linked to each of the plurality of different types of fingerprint sensors in the database, receiving a request for an optimal force range from a particular fingerprint sensor with the computer over a communication network, accessing the database with the computer to determine the optimal force range for the particular fingerprint sensor, and transmitting the optimal force range for the particular fingerprint sensor from the computer to the particular fingerprint sensor over the communication network.
Additional features of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the invention as presently perceived.